1. Field of Invention
The present invention relates to a dental gold alloy having a corrosion-resistant single phase structure and being age-hardenable at a temperature of about 37.degree. C. within the oral cavity. The industrially applicable field of the alloy of the present invention covers at least one alloy selected from a dental casting gold alloy, a dental casting gold alloy corresponding to ADA Specification Type III and Type IV, a wrought alloy etc.
2. Related Art Statement
It has hitherto been required to use a dental restorative alloy in the as-cast state to fit into a patient's occlusal condition with a tolerance on the order of several ten microns. Even if the cast is manufactured by precise casting, trial fitting and adjustment are necessary. Therefore, manufacturers specify a softening heat treatment (i.e., solution treatment, such as heating at 700.degree. C. for 10 minutes and thereafter quenching in water) and a hardening heat treatment (i.e., aging treatment, such as heating in a furnace at 450.degree. C. and thereafter slow cooling to 250.degree. C.) for obtaining an alloy which is softened at the time of adjustment and hardened enough to sufficiently withstand against deformation by biting force.
In actual clinical treatment, however, such a complicated heat treatment is hardly carried out. In practice, therefore, an alloy composition is defined to have sufficient strength in the as-cast condition and as a result, a commercial alloy becomes a quaternary or pentanary alloy, and its structure becomes complicated by coexisting multiphases. Such structure is seriously disadvantageous in view of the most important corrosion resistance as a desired property of dental alloy.